Field of the Invention
The present invention relates to an electrophotographic photosensitive member, a method for producing the electrophotographic photosensitive member, a process cartridge and an electrophotographic apparatus including the electrophotographic photosensitive member, and a hydroxygallium phthalocyanine crystal.
Description of the Related Art
At present, the oscillation wavelength of semiconductor lasers often used as image exposure devices in the field of electrophotography is a long wavelength of 650 to 820 nm. Therefore, electrophotographic photosensitive members that are highly sensitive to light having such a long wavelength are being developed. A phthalocyanine pigment is effective as a charge generation material having high sensitivity to light in such a long wavelength region. In particular, oxytitanium phthalocyanine and gallium phthalocyanine have excellent sensitivity characteristics, and various crystal forms have been reported.
Japanese Patent Laid-Open No. 5-249716 describes a hydroxygallium phthalocyanine crystal having peaks at Bragg angles (2θ±0.2°) of 7.9°, 16.5°, 24.4°, and 27.6° in CuKα X-ray diffraction. Japanese Patent Laid-Open No. 3-128973 describes an oxytitanium phthalocyanine crystal having peaks at Bragg angles (2θ±0.2°) of 9.0°, 14.2°, 23.9°, and 27.1° in CuKα X-ray diffraction.
However, sensitivity is not proportional to the electric field intensity, and thus sensitivity unevenness is easily caused due to the influence of thickness unevenness of a photosensitive layer.